Update docs

Author: marcusolsson

README.md

@@ -6,3 +6,9 @@
 A data source plugin for loading JSON APIs into [Grafana](https://grafana.com).
 
 ![Screenshot](https://raw.githubusercontent.com/marcusolsson/grafana-jsonapi-datasource/master/src/img/screenshot.png)
+
+Extract one or more values from a JSON API using [JSON Path](https://goessner.net/articles/JsonPath/). Each path results in a field in the query result. All fields need to be of the same length.
+
+The field name defaults to the name of the property referenced by the JSON Path but can be set to an **Alias**.
+
+The **Cache Time** determines the time in seconds to save the API response.

src/img/variable.png

@@ -31,6 +31,10 @@
       {
         "name": "JSON API",
         "path": "img/screenshot.png"
+      },
+      {
+        "name": "Query variable",
+        "path": "img/variable.png"
       }
     ],
     "version": "%VERSION%",